Two very compact and low power quadrature receivers for ZigBee applications are presented. Area and power savings are obtained through both current reuse and oscillator tank sharing between the I and Q paths. Since this choice can cause I and Q amplitude/phase mismatches, the conversion gain is analyzed and a technique to minimize these errors is implemented. Moreover, since using a single tank makes quadrature generation at the local oscillator level costly and power-hungry, two alternative quadrature generation techniques in the RF path are proposed, together with the corresponding input matching strategies.
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